iOS 手势操作：拖动、捏合、旋转、点按、长按、轻扫、自定义 |
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iOS 手势操作：拖动、捏合、旋转、点按、长按、轻扫、自定义
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1、UIGestureRecognizer 介绍
手势识别在 iOS 中非常重要，他极大地提高了移动设备的使用便捷性。 iOS 系统在 3.2 以后，他提供了一些常用的手势（UIGestureRecognizer 的子类），开发者可以直接使用他们进行手势操作。 UIPanGestureRecognizer（拖动） UIPinchGestureRecognizer（捏合） UIRotationGestureRecognizer（旋转） UITapGestureRecognizer（点按） UILongPressGestureRecognizer（长按） UISwipeGestureRecognizer（轻扫） 另外，可以通过继承 UIGestureRecognizer 类，实现自定义手势（手势识别器类）。 PS：自定义手势时，需要 #import ，一般需实现如下方法： 1 - (void)reset; 2 3 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event; 4 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event; 5 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event; 6 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event; 7 //以上方法在分类 UIGestureRecognizer (UIGestureRecognizerProtected) 中声明，更多方法声明请自行查看UIGestureRecognizer 的继承关系如下：
2、手势状态 在六种手势识别中，只有一种手势是离散型手势，他就是 UITapGestureRecognizer。 离散型手势的特点就是：一旦识别就无法取消，而且只会调用一次手势操作事件（初始化手势时指定的回调方法）。 换句话说其他五种手势是连续型手势，而连续型手势的特点就是：会多次调用手势操作事件，而且在连续手势识别后可以取消手势。从下图可以看出两者调用操作事件的次数是不同的：
手势状态枚举如下： 1 typedef NS_ENUM(NSInteger, UIGestureRecognizerState) { 2 UIGestureRecognizerStatePossible, // 尚未识别是何种手势操作（但可能已经触发了触摸事件），默认状态 3 UIGestureRecognizerStateBegan, // 手势已经开始，此时已经被识别，但是这个过程中可能发生变化，手势操作尚未完成 4 UIGestureRecognizerStateChanged, // 手势状态发生转变 5 UIGestureRecognizerStateEnded, // 手势识别操作完成（此时已经松开手指） 6 UIGestureRecognizerStateCancelled, // 手势被取消，恢复到默认状态 7 UIGestureRecognizerStateFailed, // 手势识别失败，恢复到默认状态 8 UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 手势识别完成，同UIGestureRecognizerStateEnded 9 }; 对于离散型手势 UITapGestureRecgnizer 要么被识别，要么失败，点按（假设点按次数设置为1，并且没有添加长按手势）下去一次不松开则此时什么也不会发生，松开手指立即识别并调用操作事件，并且状态为3（已完成）。但是连续型手势要复杂一些，就拿旋转手势来说，如果两个手指点下去不做任何操作，此时并不能识别手势（因为我们还没旋转）但是其实已经触发了触摸开始事件，此时处于状态0；如果此时旋转会被识别，也就会调用对应的操作事件，同时状态变成1（手势开始），但是状态1只有一瞬间；紧接着状态变为2（因为我们的旋转需要持续一会），并且重复调用操作事件（如果在事件中打印状态会重复打印2）；松开手指，此时状态变为3，并调用1次操作事件。 3、使用手势的步骤 使用手势很简单，分为三步： 创建手势识别器对象实例。创建时，指定一个回调方法，当手势开始，改变、或结束时，执行回调方法。 设置手势识别器对象实例的相关属性（可选部分） 添加到需要识别的 View 中。每个手势只对应一个 View，当屏幕触摸在 View 的边界内时，如果手势和预定的一样，那就会执行回调方法。 PS：一个手势只能对应一个 View，但是一个 View 可以有多个手势。建议在真机上测试这些手势，模拟器操作不太方便，可能导致认为手势失效的情况。（模拟器测试捏合和旋转手势时，按住 option 键，再用触摸板或鼠标操作） 4、举例说明 功能描述： 附加到两个图片视图 UIImageView 的有『拖动』、『捏合』、『旋转』、『点按』； 而『轻扫』和『自定义手势 KMGestureRecognizer』附加在根视图 UIView 中。 拖动：进行当前图片视图位置移动 捏合：进行当前图片视图缩放 旋转：进行当前图片视图角度旋转 点按：双击恢复当前图片视图的缩放、角度旋转、不透明度 长按：设置当前图片视图的不透明度为0.7 轻扫：左右轻扫设置两个图片视图为居中，同时以垂直居中的特定偏移量定位 自定义手势：挠痒功能，左右扫动共3次或以上，设置两个图片视图为居中，同时以水平居中的特定偏移量定位
效果如下：
KMGestureRecognizer.h 1 #import 2 3 typedef NS_ENUM(NSUInteger, Direction) { 4 DirectionUnknown, 5 DirectionLeft, 6 DirectionRight 7 }; 8 9 @interface KMGestureRecognizer : UIGestureRecognizer 10 @property (assign, nonatomic) NSUInteger tickleCount; //挠痒次数 11 @property (assign, nonatomic) CGPoint currentTickleStart; //当前挠痒开始坐标位置 12 @property (assign, nonatomic) Direction lastDirection; //最后一次挠痒方向 13 14 @endKMGestureRecognizer.m 1 #import "KMGestureRecognizer.h" 2 #import 3 4 @implementation KMGestureRecognizer 5 #define kMinTickleSpacing 20.0 6 #define kMaxTickleCount 3 7 8 - (void)reset { 9 _tickleCount = 0; 10 _currentTickleStart = CGPointZero; 11 _lastDirection = DirectionUnknown; 12 13 if (self.state == UIGestureRecognizerStatePossible) { 14 self.state = UIGestureRecognizerStateFailed; 15 } 16 } 17 18 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 19 UITouch *touch = [touches anyObject]; 20 _currentTickleStart = [touch locationInView:self.view]; //设置当前挠痒开始坐标位置 21 } 22 23 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 24 //『当前挠痒开始坐标位置』和『移动后坐标位置』进行 X 轴值比较，得到是向左还是向右移动 25 UITouch *touch = [touches anyObject]; 26 CGPoint tickleEnd = [touch locationInView:self.view]; 27 CGFloat tickleSpacing = tickleEnd.x - _currentTickleStart.x; 28 Direction currentDirection = tickleSpacing < 0 ? DirectionLeft : DirectionRight; 29 30 //移动的 X 轴间距值是否符合要求，足够大 31 if (ABS(tickleSpacing) >= kMinTickleSpacing) { 32 //判断是否有三次不同方向的动作，如果有则手势结束，将执行回调方法 33 if (_lastDirection == DirectionUnknown || 34 (_lastDirection == DirectionLeft && currentDirection == DirectionRight) || 35 (_lastDirection == DirectionRight && currentDirection == DirectionLeft)) { 36 _tickleCount++; 37 _currentTickleStart = tickleEnd; 38 _lastDirection = currentDirection; 39 40 if (_tickleCount >= kMaxTickleCount && self.state == UIGestureRecognizerStatePossible) { 41 self.state = UIGestureRecognizerStateEnded; 42 //NSLog(@"自定义手势成功，将执行回调方法"); 43 } 44 } 45 } 46 } 47 48 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 49 [self reset]; 50 } 51 52 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { 53 [self reset]; 54 } 55 56 @endViewController.h 1 #import 2 #import "KMGestureRecognizer.h" 3 4 @interface ViewController : UIViewController 5 @property (strong, nonatomic) UIImageView *imgV; 6 @property (strong, nonatomic) UIImageView *imgV2; 7 @property (strong, nonatomic) KMGestureRecognizer *customGestureRecognizer; 8 9 @endViewController.m 1 #import "ViewController.h" 2 3 @interface ViewController () 4 - (void)handlePan:(UIPanGestureRecognizer *)recognizer; 5 - (void)handlePinch:(UIPinchGestureRecognizer *)recognizer; 6 - (void)handleRotation:(UIRotationGestureRecognizer *)recognizer; 7 - (void)handleTap:(UITapGestureRecognizer *)recognizer; 8 - (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer; 9 - (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer; 10 - (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer; 11 12 - (void)bindPan:(UIImageView *)imgVCustom; 13 - (void)bindPinch:(UIImageView *)imgVCustom; 14 - (void)bindRotation:(UIImageView *)imgVCustom; 15 - (void)bindTap:(UIImageView *)imgVCustom; 16 - (void)bindLongPress:(UIImageView *)imgVCustom; 17 - (void)bindSwipe; 18 - (void)bingCustomGestureRecognizer; 19 - (void)layoutUI; 20 @end 21 22 @implementation ViewController 23 24 - (void)viewDidLoad { 25 [super viewDidLoad]; 26 27 [self layoutUI]; 28 } 29 30 - (void)didReceiveMemoryWarning { 31 [super didReceiveMemoryWarning]; 32 // Dispose of any resources that can be recreated. 33 } 34 35 #pragma mark - 处理手势操作 36 /** 37 * 处理拖动手势 38 * 39 * @param recognizer 拖动手势识别器对象实例 40 */ 41 - (void)handlePan:(UIPanGestureRecognizer *)recognizer { 42 //视图前置操作 43 [recognizer.view.superview bringSubviewToFront:recognizer.view]; 44 45 CGPoint center = recognizer.view.center; 46 CGFloat cornerRadius = recognizer.view.frame.size.width / 2; 47 CGPoint translation = [recognizer translationInView:self.view]; 48 //NSLog(@"%@", NSStringFromCGPoint(translation)); 49 recognizer.view.center = CGPointMake(center.x + translation.x, center.y + translation.y); 50 [recognizer setTranslation:CGPointZero inView:self.view]; 51 52 if (recognizer.state == UIGestureRecognizerStateEnded) { 53 //计算速度向量的长度，当他小于200时，滑行会很短 54 CGPoint velocity = [recognizer velocityInView:self.view]; 55 CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y)); 56 CGFloat slideMult = magnitude / 200; 57 //NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult); //e.g. 397.973175, slideMult: 1.989866 58 59 //基于速度和速度因素计算一个终点 60 float slideFactor = 0.1 * slideMult; 61 CGPoint finalPoint = CGPointMake(center.x + (velocity.x * slideFactor), 62 center.y + (velocity.y * slideFactor)); 63 //限制最小［cornerRadius］和最大边界值［self.view.bounds.size.width - cornerRadius］，以免拖动出屏幕界限 64 finalPoint.x = MIN(MAX(finalPoint.x, cornerRadius), 65 self.view.bounds.size.width - cornerRadius); 66 finalPoint.y = MIN(MAX(finalPoint.y, cornerRadius), 67 self.view.bounds.size.height - cornerRadius); 68 69 //使用 UIView 动画使 view 滑行到终点 70 [UIView animateWithDuration:slideFactor*2 71 delay:0 72 options:UIViewAnimationOptionCurveEaseOut 73 animations:^{ 74 recognizer.view.center = finalPoint; 75 } 76 completion:nil]; 77 } 78 } 79 80 /** 81 * 处理捏合手势 82 * 83 * @param recognizer 捏合手势识别器对象实例 84 */ 85 - (void)handlePinch:(UIPinchGestureRecognizer *)recognizer { 86 CGFloat scale = recognizer.scale; 87 recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, scale, scale); //在已缩放大小基础下进行累加变化；区别于：使用 CGAffineTransformMakeScale 方法就是在原大小基础下进行变化 88 recognizer.scale = 1.0; 89 } 90 91 /** 92 * 处理旋转手势 93 * 94 * @param recognizer 旋转手势识别器对象实例 95 */ 96 - (void)handleRotation:(UIRotationGestureRecognizer *)recognizer { 97 recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation); 98 recognizer.rotation = 0.0; 99 } 100 101 /** 102 * 处理点按手势 103 * 104 * @param recognizer 点按手势识别器对象实例 105 */ 106 - (void)handleTap:(UITapGestureRecognizer *)recognizer { 107 UIView *view = recognizer.view; 108 view.transform = CGAffineTransformMakeScale(1.0, 1.0); 109 view.transform = CGAffineTransformMakeRotation(0.0); 110 view.alpha = 1.0; 111 } 112 113 /** 114 * 处理长按手势 115 * 116 * @param recognizer 点按手势识别器对象实例 117 */ 118 - (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer { 119 //长按的时候，设置不透明度为0.7 120 recognizer.view.alpha = 0.7; 121 } 122 123 /** 124 * 处理轻扫手势 125 * 126 * @param recognizer 轻扫手势识别器对象实例 127 */ 128 - (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer { 129 //代码块方式封装操作方法 130 void (^positionOperation)() = ^() { 131 CGPoint newPoint = recognizer.view.center; 132 newPoint.y -= 20.0; 133 _imgV.center = newPoint; 134 135 newPoint.y += 40.0; 136 _imgV2.center = newPoint; 137 }; 138 139 //根据轻扫方向，进行不同控制 140 switch (recognizer.direction) { 141 case UISwipeGestureRecognizerDirectionRight: { 142 positionOperation(); 143 break; 144 } 145 case UISwipeGestureRecognizerDirectionLeft: { 146 positionOperation(); 147 break; 148 } 149 case UISwipeGestureRecognizerDirectionUp: { 150 break; 151 } 152 case UISwipeGestureRecognizerDirectionDown: { 153 break; 154 } 155 } 156 } 157 158 /** 159 * 处理自定义手势 160 * 161 * @param recognizer 自定义手势识别器对象实例 162 */ 163 - (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer { 164 //代码块方式封装操作方法 165 void (^positionOperation)() = ^() { 166 CGPoint newPoint = recognizer.view.center; 167 newPoint.x -= 20.0; 168 _imgV.center = newPoint; 169 170 newPoint.x += 40.0; 171 _imgV2.center = newPoint; 172 }; 173 174 positionOperation(); 175 } 176 177 178 #pragma mark - 绑定手势操作 179 /** 180 * 绑定拖动手势 181 * 182 * @param imgVCustom 绑定到图片视图对象实例 183 */ 184 - (void)bindPan:(UIImageView *)imgVCustom { 185 UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self 186 action:@selector(handlePan:)]; 187 [imgVCustom addGestureRecognizer:recognizer]; 188 } 189 190 /** 191 * 绑定捏合手势 192 * 193 * @param imgVCustom 绑定到图片视图对象实例 194 */ 195 - (void)bindPinch:(UIImageView *)imgVCustom { 196 UIPinchGestureRecognizer *recognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self 197 action:@selector(handlePinch:)]; 198 [imgVCustom addGestureRecognizer:recognizer]; 199 //[recognizer requireGestureRecognizerToFail:imgVCustom.gestureRecognizers.firstObject]; 200 } 201 202 /** 203 * 绑定旋转手势 204 * 205 * @param imgVCustom 绑定到图片视图对象实例 206 */ 207 - (void)bindRotation:(UIImageView *)imgVCustom { 208 UIRotationGestureRecognizer *recognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self 209 action:@selector(handleRotation:)]; 210 [imgVCustom addGestureRecognizer:recognizer]; 211 } 212 213 /** 214 * 绑定点按手势 215 * 216 * @param imgVCustom 绑定到图片视图对象实例 217 */ 218 - (void)bindTap:(UIImageView *)imgVCustom { 219 UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self 220 action:@selector(handleTap:)]; 221 //使用一根手指双击时，才触发点按手势识别器 222 recognizer.numberOfTapsRequired = 2; 223 recognizer.numberOfTouchesRequired = 1; 224 [imgVCustom addGestureRecognizer:recognizer]; 225 } 226 227 /** 228 * 绑定长按手势 229 * 230 * @param imgVCustom 绑定到图片视图对象实例 231 */ 232 - (void)bindLongPress:(UIImageView *)imgVCustom { 233 UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)]; 234 recognizer.minimumPressDuration = 0.5; //设置最小长按时间；默认为0.5秒 235 [imgVCustom addGestureRecognizer:recognizer]; 236 } 237 238 /** 239 * 绑定轻扫手势；支持四个方向的轻扫，但是不同的方向要分别定义轻扫手势 240 */ 241 - (void)bindSwipe { 242 //向右轻扫手势 243 UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self 244 action:@selector(handleSwipe:)]; 245 recognizer.direction = UISwipeGestureRecognizerDirectionRight; //设置轻扫方向；默认是 UISwipeGestureRecognizerDirectionRight，即向右轻扫 246 [self.view addGestureRecognizer:recognizer]; 247 [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //设置以自定义挠痒手势优先识别 248 249 //向左轻扫手势 250 recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self 251 action:@selector(handleSwipe:)]; 252 recognizer.direction = UISwipeGestureRecognizerDirectionLeft; 253 [self.view addGestureRecognizer:recognizer]; 254 [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //设置以自定义挠痒手势优先识别 255 } 256 257 /** 258 * 绑定自定义挠痒手势；判断是否有三次不同方向的动作，如果有则手势结束，将执行回调方法 259 */ 260 - (void)bingCustomGestureRecognizer { 261 //当 recognizer.state 为 UIGestureRecognizerStateEnded 时，才执行回调方法 handleCustomGestureRecognizer: 262 263 //_customGestureRecognizer = [KMGestureRecognizer new]; 264 _customGestureRecognizer = [[KMGestureRecognizer alloc] initWithTarget:self 265 action:@selector(handleCustomGestureRecognizer:)]; 266 [self.view addGestureRecognizer:_customGestureRecognizer]; 267 } 268 269 - (void)layoutUI { 270 //图片视图 _imgV 271 UIImage *img = [UIImage imageNamed:@"Emoticon_tusiji_icon"]; 272 CGFloat cornerRadius = img.size.width; 273 _imgV = [[UIImageView alloc] initWithImage:img]; 274 _imgV.frame = CGRectMake(20.0, 20.0, 275 cornerRadius * 2, cornerRadius * 2); 276 _imgV.userInteractionEnabled = YES; 277 _imgV.layer.masksToBounds = YES; 278 _imgV.layer.cornerRadius = cornerRadius; 279 _imgV.layer.borderWidth = 2.0; 280 _imgV.layer.borderColor = [UIColor grayColor].CGColor; 281 [self.view addSubview:_imgV]; 282 283 //图片视图 _imgV2 284 img = [UIImage imageNamed:@"Emoticon_tusiji_icon2"]; 285 cornerRadius = img.size.width; 286 _imgV2 = [[UIImageView alloc] initWithImage:img]; 287 _imgV2.frame = CGRectMake(20.0, 40.0 + _imgV.frame.size.height, 288 cornerRadius * 2, cornerRadius * 2); 289 _imgV2.userInteractionEnabled = YES; 290 _imgV2.layer.masksToBounds = YES; 291 _imgV2.layer.cornerRadius = cornerRadius; 292 _imgV2.layer.borderWidth = 2.0; 293 _imgV2.layer.borderColor = [UIColor orangeColor].CGColor; 294 [self.view addSubview:_imgV2]; 295 296 297 [self bindPan:_imgV]; 298 [self bindPinch:_imgV]; 299 [self bindRotation:_imgV]; 300 [self bindTap:_imgV]; 301 [self bindLongPress:_imgV]; 302 303 [self bindPan:_imgV2]; 304 [self bindPinch:_imgV2]; 305 [self bindRotation:_imgV2]; 306 [self bindTap:_imgV2]; 307 [self bindLongPress:_imgV2]; 308 309 //为了处理手势识别优先级的问题，这里需先绑定自定义挠痒手势 310 [self bingCustomGestureRecognizer]; 311 [self bindSwipe]; 312 } 313 314 @end
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